There have been loads of comments by so many people. I will try to summarize what they said

What.cd is the biggest tracker for music lovers. It has the largest number of artists and albums, and ofc, 95,000 registered users with close to 500,000 torrents between them. They have recently expanded their collection of 100% FLACs.
What.cd is being closely followed by Waffles. Its easier to put it this way, if its not on waffles, you can try your luck with What.cd , and vice versa. These two trackers look after the needs of most music lovers.
Moving on, if you listen to a specific genre, there are trackers dedicated to them. Like TT for Trance, DB9 for DnB, LzTr for classical and Jazz and so on.
If you are very particular about the formats you like your music in, Pedro's BTMusic is the best for FLAC. (They have the highest quality rips with equal emphasis on cover art as well). E**** is also another tracker dedicated to FLACs and lossless content.
With that, i would like to add that there is no 'True' winner, when we talk about music trackers in general. Its all about your choices, preferences and tastes.